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Recent Advances in the Synthesis, Functionalization and Applications of Pyrazole-Type Compounds III

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Organic Chemistry".

Deadline for manuscript submissions: 31 October 2024 | Viewed by 1883

Special Issue Editors


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Guest Editor
LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
Interests: organic synthesis; development of sustainable organic synthesis methodologies; ohmic-heating-assisted synthesis; synthesis, functionalization and structural characterization of oxygen- and nitrogen-based heterocyclic compounds; development of molecules for medicinal applications
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Special Issue Information

Dear Colleagues,

Pyrazoles continue to attract the interest of chemists worldwide, and to generate new chemistry, due to their remarkable biological activities and occurrence in many low-molecular-weight compounds present in several marketed drugs (e.g., Celebrex® and Viagra®). Pyrazoles are also found within a variety of agrochemicals (fungicides, insecticides, and herbicides) and are versatile scaffolds for synthetic manipulations. Due to their huge importance, this third edition of the Special Issue “Recent Advances in the Synthesis, Functionalization and Applications of Pyrazole-Type Compounds” aims to highlight the most recent advances in the chemistry of pyrazole derivatives. Owing to the success of the two previous editions of this Special Issue (the last one ranked in the top ten Special Issues that collected the most papers in 2022), this third edition aims to cover a broad range of important topics of the chemistry of these nitrogen heterocyclic compounds.

We welcome the submission of original research articles and reviews that discuss new reactivity patterns, the synthesis of pyrazoles with additional fused rings, new methods for pyrazole transformation, pyrazole metal complexes, aspects of medicinal chemistry incorporating the pyrazole system, and other important features of pyrazoles’ chemistry.

Dr. Vera L. M. Silva
Prof. Dr. Artur M. S. Silva
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • pyrazoles
  • pyrazolines
  • synthesis
  • functionalization
  • transformation
  • complexes
  • applications

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Published Papers (1 paper)

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Research

26 pages, 4252 KiB  
Article
Synthesis and Characterization of New Pyrano[2,3-c]pyrazole Derivatives as 3-Hydroxyflavone Analogues
by Arminas Urbonavičius, Sonata Krikštolaitytė, Aurimas Bieliauskas, Vytas Martynaitis, Joana Solovjova, Asta Žukauskaitė, Eglė Arbačiauskienė and Algirdas Šačkus
Molecules 2023, 28(18), 6599; https://doi.org/10.3390/molecules28186599 - 13 Sep 2023
Viewed by 1227
Abstract
In this paper, an efficient synthetic route from pyrazole-chalcones to novel 6-aryl-5-hydroxy-2-phenylpyrano[2,3-c]pyrazol-4(2H)-ones as 3-hydroxyflavone analogues is described. The methylation of 5-hydroxy-2,6-phenylpyrano[2,3-c]pyrazol-4(2H)-one with methyl iodide in the presence of a base yielded a compound containing a [...] Read more.
In this paper, an efficient synthetic route from pyrazole-chalcones to novel 6-aryl-5-hydroxy-2-phenylpyrano[2,3-c]pyrazol-4(2H)-ones as 3-hydroxyflavone analogues is described. The methylation of 5-hydroxy-2,6-phenylpyrano[2,3-c]pyrazol-4(2H)-one with methyl iodide in the presence of a base yielded a compound containing a 5-methoxy group, while the analogous reaction of 5-hydroxy-2-phenyl-6-(pyridin-4-yl)pyrano[2,3-c]pyrazol-4(2H)-one led to the zwitterionic 6-(N-methylpyridinium)pyrano[2,3-c]pyrazol derivative. The treatment of 5-hydroxy-2,6-phenylpyrano[2,3-c]pyrazol-4(2H)-one with triflic anhydride afforded a 5-trifloylsubstituted compound, which was further used in carbon–carbon bond forming Pd-catalyzed coupling reactions to yield 5-(hetero)aryl- and 5-carbo-functionalized pyrano[2,3-c]pyrazoles. The excited-state intramolecular proton transfer (ESIPT) reaction of 5-hydroxypyrano[2,3-c]pyrazoles from the 5-hydroxy moiety to the carbonyl group in polar protic, polar aprotic, and nonpolar solvents was observed, resulting in well-resolved two-band fluorescence. The structures of the novel heterocyclic compounds were confirmed by 1H-, 13C-, 15N-, and 19F-NMR spectroscopy, HRMS, and single-crystal X-ray diffraction data. Full article
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